Dictating is a new skill for most people.
Your elocution will be better because you know what you will say. Talk without thinking, and you are likely to find that words get mumbled as you change your mind about what you are saying.
Dragon NaturallySpeaking understands “natural” speech but not “conversational” speech. Pretend that you are a broadcast journalist reading the news from behind an anchor desk, a lecturer, or a courtroom lawyer. Don't talk as though you are talking to your friend over coffee or as you would talk at a cocktail party.
If you have the elocution/diction/pronunciation of a broadcaster or an actor, you'll have few accuracy problems with NaturallySpeaking! For the rest of us, listening to our recorded speech can be enlightening.
When I play back words from my dictation, I frequently discover that the software actually recognized the word that I said, not the word I meant to say. I may have skipped a sound, used one sound when I should have repeated the same sound, etc. After years of using these programs, I find myself speaking more clearly than when I started using these programs.
You don't need to talk loudly, nor should you whisper (whispering is very hard on the vocal cords). If yours is a very quiet voice, you may be better off with a microphone such as the Emkay or Philips Speech Mike which tend to amplify sounds a little more, or a “hot” sound card like the AudioPCI.
If you are going to be thinking of what to say, looking up material, etc., turn off the microphone using the numeric "+" key (Mic On/Off toggle Hot Key) or mute switch or tell it "Go To Sleep" or "Microphone Off".
If you wish/need to study enunciation in detail, the book Speaking Clearly is a good resource (IBSN 0-07-025919-4). If you average more than one person per day asking you to repeat something because they didn't understand the words you said, buying this book and applying its lessons should be done before buying NaturallySpeaking.
With speech pathology problems, you may not be able to enunciate well. If so, NaturallySpeaking may not work well -- but it may work very well. If your speech is consistent, NaturallySpeaking can be trained. DragonDictate might be a better product than NaturallySpeaking if you have severe speech problems.
I've had the pleasure of working with one individual with a spinal cord injury where I can say that his computer understands him better than anyone besides his wife. Thanks, Dragon, for helping such a person communicate with a wider audience!
Updated January 2001